A conveying apparatus for epoxy resin adhesive packaging

Abstract

The utility model discloses a conveying equipment for epoxy resin adhesive packaging belongs to epoxy resin adhesive production technical field. In view of the quantitative effect of existing conveying equipment is not good enough, is easy to lead to the unstable quality of packaging, and quantitative adjustment is complicated, and the problem of time -consuming and labor -intensive and low efficiency of debugging, the equipment sets up piston cylinder and adjustment cylinder to form quantitative cavity in the connecting cylinder, realizes adhesive quantitative storage conveying, drive assembly passes through air cylinder, proximity switch and time relay, controls piston cylinder automatic reciprocating motion, guarantees quantitative interval conveying automation, and adjustment assembly cooperates with motor drive gear and screw rod, and the volume of quantitative cavity is changed by adjusting adjustment cylinder position, and different packaging specifications can be adapted without disassembling. The equipment is used for epoxy resin adhesive packaging conveying, can promote quantitative accuracy and quality stability, simplifies the adjustment operation, improves production efficiency, adapts the large -scale packaging production demand.

Description

Technical Field

[0001] This utility model relates to the field of epoxy resin adhesive production technology, and in particular to a conveying device for packaging epoxy resin adhesives. Background Technology

[0002] Epoxy resin adhesives are a class of engineering adhesives formulated from epoxy resin base materials, curing agents, diluents, accelerators, and fillers. In the packaging production process of epoxy resin adhesives, conveying equipment is needed to quantitatively transport the adhesive to the packaging stage to ensure consistency in weight or volume for each batch of packaged products. However, existing conveying equipment still has the following problems in use:

[0003] Existing conventional conveying equipment is not effective enough in quantitative conveying of epoxy resin adhesives. It is inconvenient to control the amount of adhesive used in each delivery, which can easily lead to overweight or underweight products during subsequent packaging, affecting product quality stability. At the same time, the quantitative adjustment operation of some equipment is cumbersome. When it is necessary to adjust the conveying volume according to different packaging specifications, it is often necessary to disassemble the equipment parts for readjustment, which is time-consuming and labor-intensive, seriously affecting production efficiency.

[0004] To address the aforementioned problems, this utility model document proposes a conveying device for packaging epoxy resin adhesives. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing epoxy adhesive conveying equipment, such as insufficient quantitative effect, unstable packaging quality, cumbersome equipment adjustment, time and labor costs, and reduced work efficiency. Therefore, this invention proposes a conveying device for epoxy resin adhesive packaging.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A conveying device for packaging epoxy resin adhesives, comprising:

[0008] The storage hopper and the connecting cylinder are provided. The top of the storage hopper is provided with a feeding port, and the bottom of the storage hopper is connected to the connecting cylinder. One end of the connecting cylinder is sealed and slidably connected to a piston cylinder, and the other end of the connecting cylinder is sealed and slidably connected to an adjusting cylinder. The piston cylinder and the adjusting cylinder form a metering chamber inside the connecting cylinder.

[0009] A drive assembly, which is connected to the piston cylinder, is used to drive the piston cylinder to reciprocate within the connecting cylinder.

[0010] An adjustment assembly, which is connected to the adjustment cylinder, is used to adjust the position of the adjustment cylinder within the connecting cylinder;

[0011] When the regulating cylinder moves, the volume of the metering chamber changes, and when the piston cylinder reciprocates, the epoxy resin adhesive in the metering chamber can be squeezed out.

[0012] In one possible design, the drive assembly includes a first fixed plate and a cylinder. The first fixed plate is fixed to one end of the piston cylinder, and the cylinder is fixed to one side of the connecting cylinder by a bracket. The piston rod of the cylinder is connected to the first fixed plate to drive the piston cylinder to push and pull.

[0013] In one possible design, the adjusting assembly includes a second fixed plate, a motor, a driving gear, a screw, and a driven gear. The second fixed plate is fixed to one end of the adjusting cylinder, the motor is fixed to the second fixed plate, the output shaft of the motor is connected to the driving gear, the screw is rotatably connected to the second fixed plate, and the driven gear is fixed to one end of the screw and meshes with the driving gear. A limiting plate is provided on one side of the connecting cylinder, and the screw is threadedly engaged with the limiting plate. When the motor drives, the screw rotates, causing the second fixed plate and the adjusting cylinder to move.

[0014] In one possible design, the system further includes a guide rod and a first proximity switch. The guide rod is fixed to one side of the first fixed plate and slides through the limiting plate. The first proximity switch is located at one end of the guide rod and cooperates with one end of the screw. The system also includes a fixed rod and a second proximity switch. The fixed rod is fixed to one end of the connecting cylinder near the piston cylinder and slides through the first fixed plate. The second proximity switch is located at one end of the fixed rod and cooperates with the first fixed plate. The first and second proximity switches are electrically connected to the cylinder and are used to control the reciprocating motion of the cylinder.

[0015] In one possible design, one end of the fixing rod is provided with a time relay, which is electrically connected to a second proximity switch and is used to delay the trigger signal of the second proximity switch.

[0016] In one possible design, the regulating cylinder has a feed inlet at one end near the piston cylinder, and the feed inlet has a porous mesh structure to initially block the epoxy resin adhesive entering the metering chamber; the bottom discharge end of the storage tank is equipped with a one-way valve to prevent the epoxy resin adhesive from flowing back.

[0017] In one possible design, a feed pump is provided on the bottom inner wall of the regulating cylinder, and the outlet of the feed pump is connected to a discharge pipe. The discharge pipe passes through one end of the regulating cylinder and is used to transport the metered epoxy resin adhesive to the next device.

[0018] In one possible design, multiple limiting plates are provided, and the screw passes through multiple limiting plates and is threadedly engaged with the limiting plate near the second fixing plate.

[0019] In this application, epoxy resin adhesive enters the storage tank through the feed port, and then flows into the connecting cylinder through the discharge pipe at the bottom of the storage tank; one end of the connecting cylinder is sealed and slides through the piston cylinder, and the other end is sealed and slides through the regulating cylinder. The gap between the piston cylinder and the regulating cylinder forms a metering cavity in the connecting cylinder to accommodate a metered amount of epoxy resin adhesive; the one-way valve inside the discharge pipe at the bottom of the storage tank ensures that the epoxy resin adhesive can only flow in one direction to prevent backflow; the cylinder of the drive assembly pushes the first fixed plate through the piston rod, thereby causing the piston cylinder to move horizontally within the connecting cylinder;

[0020] When the piston cylinder moves into the connecting cylinder, the volume of the metering chamber decreases, which can press the epoxy resin adhesive towards the regulating cylinder. At this time, the piston cylinder can also seal the discharge port at the bottom of the storage tank. During this process, the guide rod can move synchronously with the piston cylinder. When the first proximity switch at one end of the guide rod approaches or even abuts against one end of the screw, a signal can be triggered to control the cylinder to switch its working state in order to complete the reverse push of the piston cylinder.

[0021] When the piston cylinder moves outward, the discharge port is opened again, and the epoxy resin adhesive in the storage tank can re-enter the metering chamber. During this process, when the piston cylinder moves to the point where the first fixed plate approaches or even abuts against the second proximity switch, a signal can be triggered again to control the cylinder to switch its working state. After the second proximity switch is triggered, the time relay can delay the start of the signal, thereby ensuring that the epoxy resin adhesive can fully enter the metering chamber.

[0022] The adjustment assembly is driven by a motor to drive the active gear, which meshes with the driven gear. The driven gear is fixed to one end of the screw. When the screw rotates, it engages with one of the limiting plates by thread, which drives the second fixed plate and the adjustment cylinder to move horizontally, thereby changing the position of the adjustment cylinder in the connecting cylinder. This allows the volume of the metering chamber to be adjusted to meet different metering requirements.

[0023] A feed inlet is opened at one end of the regulating cylinder near the piston cylinder. The feed inlet has a porous mesh structure inside, which uses tension to initially block the epoxy resin adhesive entering the metering chamber. Subsequently, under the push of the piston cylinder, it can ensure that the epoxy resin adhesive is fully discharged. A feed pump is installed on the inner wall of the bottom of the regulating cylinder. The outlet of the feed pump is connected to the discharge pipe. When the epoxy resin adhesive in the metering chamber is pressed into the regulating cylinder, the feed pump starts and transports the adhesive to the next stage of equipment through the discharge pipe.

[0024] The entire working process, through the coordinated operation of various components, enables the quantitative and interval delivery of epoxy resin adhesives, which facilitates the fulfillment of epoxy resin adhesive packaging requirements.

[0025] Beneficial effects: The conveying equipment for packaging epoxy resin adhesives described in this utility model forms a quantitative cavity in the connecting cylinder through the piston cylinder and the adjusting cylinder, which can accurately realize the quantitative storage and conveying of adhesives, effectively solve the problem of insufficient quantitative accuracy of traditional equipment, ensure the consistency of the weight or capacity of packaged products, and improve the stability of product quality.

[0026] In this utility model, the conveying equipment for packaging epoxy resin adhesives uses a drive component equipped with a proximity switch and a time relay to realize automatic control of the reciprocating motion of the piston cylinder and ensure that the time for replenishing adhesive in the metering chamber is the same each time, which further improves the metering of adhesives and effectively realizes the automated operation of metering interval conveying of adhesives, which is more in line with the needs of large-scale packaging production.

[0027] In this utility model, the conveying equipment for packaging epoxy resin adhesives uses a motor-driven gear transmission to rotate the screw and adjust the position of the adjusting cylinder. This allows for flexible changes in the volume of the metering chamber, adapting to different packaging requirements. The metering adjustment can be completed without disassembling the equipment, making the operation simple and quick, and significantly improving production efficiency.

[0028] In this invention, the epoxy resin adhesive packaging conveying device forms a metering cavity through a piston cylinder and an adjusting cylinder, which can deliver adhesive in a timed and metered manner to ensure the consistency of product packaging quality. The drive component, combined with a proximity switch and a time relay, realizes the automatic reciprocating motion of the piston cylinder, ensuring the automation of metered interval delivery, and is suitable for large-scale production. The adjusting component can flexibly adjust the volume of the metering cavity, adapting to different packaging specifications without disassembling the equipment, making operation convenient and effectively improving production efficiency. Attached Figure Description

[0029] Figure 1 This is a three-dimensional structural diagram of a conveying device for packaging epoxy resin adhesives proposed in this utility model.

[0030] Figure 2 This is a three-dimensional structural diagram of a conveying device for packaging epoxy resin adhesives proposed in this utility model from another perspective.

[0031] Figure 3 This is a cross-sectional structural diagram of a conveying device for packaging epoxy resin adhesives according to the present invention.

[0032] Figure 4 This is a schematic diagram showing the disassembled structure of a conveying device for packaging epoxy resin adhesives according to the present invention.

[0033] Figure 5 This is a schematic diagram of the adjusting component structure of a conveying device for packaging epoxy resin adhesives proposed in this utility model;

[0034] Figure 6 This is a schematic diagram of the end structure of the fixed rod of a conveying device for packaging epoxy resin adhesives proposed in this utility model.

[0035] In the diagram: 1. Storage tank; 2. Connecting cylinder; 3. Piston cylinder; 4. Adjusting cylinder; 5. Feed inlet; 6. First fixing plate; 7. Fixing rod; 8. Cylinder; 9. One-way valve; 10. Feed port; 11. Metering chamber; 12. Feed pump; 13. Discharge pipe; 14. Guide rod; 15. First proximity switch; 16. Second fixing plate; 17. Screw; 18. Limiting plate; 19. Motor; 20. Drive gear; 21. Driven gear; 22. Second proximity switch; 23. Time relay. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0037] In one embodiment: Refer to Figure 1-6 A conveying device includes: a storage tank 1, a connecting cylinder 2, a piston cylinder 3, an adjusting cylinder 4, a drive assembly, an adjusting assembly, a conveying pump 12, and related auxiliary components.

[0038] In this embodiment, a feed port 5 is fixedly provided through the top of the storage tank 1 for adding epoxy resin adhesive into the storage tank 1; the discharge end of the bottom of the storage tank 1 is fixedly provided through the outer wall of the connecting cylinder 2 and extends into the connecting cylinder 2.

[0039] In this embodiment, the piston cylinder 3 is sealed and slidably passed through one end of the connecting cylinder 2, and the regulating cylinder 4 is sealed and slidably passed through the other end; the gap between the two ends of the piston cylinder 3 and the regulating cylinder 4 forms a metering cavity 11 inside the connecting cylinder 2, which is used to meter the epoxy resin adhesive being transported; the regulating cylinder 4 has an inlet 10 at one end near the piston cylinder 3, and the inlet 10 has a porous mesh structure similar to a filter screen inside, which is used to initially block the epoxy resin adhesive entering the metering cavity 11 under tension.

[0040] In this embodiment, the drive assembly is used to drive and detect the piston cylinder 3, so as to realize the reciprocating piston movement of the piston cylinder 3 within the connecting cylinder 2. Specifically, the drive assembly includes a first fixing plate 6 fixedly installed at one end of the piston cylinder 3, and a cylinder 8 fixedly installed on one side of the connecting cylinder 2 via a bracket. One end of the piston rod of the cylinder 8 is fixedly connected to one side of the first fixing plate 6. By extending and retracting the piston rod of the cylinder 8, the piston cylinder 3 can be pushed and pulled. A guide rod 14 is fixedly installed on one side of the first fixing plate 6. The guide rod 14 is located on the side of the connecting cylinder 2 away from the cylinder 8. One end of the guide rod 14 slides through multiple adjacent limiting plates 18, and a first proximity switch 15 is fixedly installed on one end of the guide rod 14. The connecting cylinder 2 is close to the piston cylinder 3. A fixing rod 7 is fixedly installed at one end, and one end of the fixing rod 7 slides through the first fixing plate 6. A second proximity switch 22 is fixedly installed at the other end of the fixing rod 7. The second proximity switch 22 cooperates with the side of the first fixing plate 6 away from the connecting cylinder 2. Both the first proximity switch 15 and the second proximity switch 22 are electrically connected to the cylinder 8. When the first fixing plate 6 moves to the position corresponding to the first proximity switch 15 or the second proximity switch 22, a trigger signal can be triggered to control the cylinder 8 to complete the corresponding switching of working states, so as to realize the corresponding extension and retraction of its piston rod. A time relay 23 is also fixedly installed at one end of the fixing rod 7. The time relay 23 is electrically connected to the second proximity switch 22 to complete the delayed triggering of the electrical signal of the second proximity switch 22. Among them, the first proximity switch 15 and the second proximity switch 22 are the same as those in the patent with publication number CN223429906U, and the time relay 23 is the same as those in the patent with publication number CN223417123U.

[0041] In this embodiment, the adjustment assembly is used to adjust the position of the adjustment cylinder 4 within the connecting cylinder 2. The adjustment assembly includes a second fixing plate 16 fixedly installed at one end of the adjustment cylinder 4. A protrusion is provided on one side of the second fixing plate 16, and a motor 19 is fixedly installed on one side of the protrusion. One end of the output shaft of the motor 19 rotatably passes through one side of the protrusion of the second fixing plate 16 and is fixedly installed with a drive gear 20. A screw 17 rotatably passes through one side of the second fixing plate 16, and a driven gear 21 is fixedly installed at one end of the screw 17. 20 meshes with the driven gear 21; multiple limiting plates 18 are fixedly installed on one side of the connecting cylinder 2, and the other end of the screw 17 passes through multiple adjacent limiting plates 18, and the screw 17 is threadedly engaged with one of the limiting plates 18. The driving gear 20 is driven to rotate by the motor 19, which in turn drives the driven gear 21 and the screw 17 to rotate, thus completing the horizontal drive of the adjusting cylinder 4; one end of the screw 17 is engaged with the first proximity switch 15. When the first proximity switch 15 moves to the corresponding position close to one end of the screw 17, a relevant signal can be triggered.

[0042] This application can be used in the field of epoxy resin adhesive production technology, or in other fields applicable to this application.

[0043] In another embodiment: Reference Figure 1 , 3 A conveying device for packaging epoxy resin adhesives, which is applied to the field of epoxy resin adhesive production technology.

[0044] In this embodiment, a feed pump 12 is fixedly installed on the bottom inner wall of the regulating cylinder 4. The feed pump 12 is a diaphragm pump with the model number DP-100A. A discharge pipe 13 is fixedly installed at one end of the discharge port of the feed pump 12. One end of the discharge pipe 13 is fixedly inserted through one end of the regulating cylinder 4 and is used to connect to the next stage conveying equipment to convey the metered epoxy resin adhesive.

[0045] In this embodiment, a one-way valve 9 is fixedly installed inside the discharge pipe at the bottom of the storage tank 1 to achieve one-way flow of the epoxy resin adhesive and prevent it from flowing back.

[0046] However, as is well known to those skilled in the art, the working principles and wiring methods of the feed pump 12, motor 19, first proximity switch 15, second proximity switch 22 and time relay 23 are all conventional means or common knowledge, and will not be described in detail here. Those skilled in the art can make any selections according to their needs or convenience.

[0047] The working principle and usage process of this technical solution are as follows:

[0048] Epoxy resin adhesive enters the storage tank 1 through the feed port 5, and then flows into the connecting cylinder 2 through the discharge end at the bottom of the storage tank 1. One end of the connecting cylinder 2 is sealed and slides through the piston cylinder 3, and the other end is sealed and slides through the regulating cylinder 4. The gap between the piston cylinder 3 and the regulating cylinder 4 forms a metering chamber 11 in the connecting cylinder 2 to hold a metered amount of epoxy resin adhesive. The one-way valve 9 installed inside the discharge end at the bottom of the storage tank 1 ensures that the epoxy resin adhesive can only flow in one direction and prevents backflow. The cylinder 8 of the drive assembly pushes the first fixed plate 6 through the piston rod, thereby causing the piston cylinder 3 to move horizontally within the connecting cylinder 2.

[0049] When the piston cylinder 3 moves into the connecting cylinder 2, the volume of the metering chamber 11 decreases, which can press the epoxy resin adhesive towards the regulating cylinder 4. At this time, the piston cylinder 3 can seal the discharge port at the bottom of the storage tank 1. During this process, the guide rod 14 can move synchronously with the piston cylinder 3. When the first proximity switch 15 at one end of the guide rod 14 approaches or even abuts against one end of the screw 17, a signal can be triggered to control the cylinder 8 to switch its working state in order to complete the reverse push back of the piston cylinder 3.

[0050] When the piston cylinder 3 moves outward, the discharge port at the bottom of the storage tank 1 is opened again, and the epoxy resin adhesive in the storage tank 1 can re-enter the metering chamber 11. During this process, when the piston cylinder 3 moves to the point where the first fixed plate 6 approaches or even abuts against the second proximity switch 22, a signal can be triggered again to control the cylinder 8 to switch its working state. When the second proximity switch 22 is triggered, the time relay 23 can delay the start of the signal, thereby ensuring that the epoxy resin adhesive can fully enter the metering chamber 11.

[0051] The adjustment assembly drives the drive gear 20 through the motor 19. The drive gear 20 meshes with the driven gear 21, which is fixed to one end of the screw 17. When the screw 17 rotates, it drives the second fixed plate 16 and the adjustment cylinder 4 to move horizontally due to the threaded engagement with one of the limiting plates 18. This changes the position of the adjustment cylinder 4 in the connecting cylinder 2, and the volume of the metering chamber 11 can be adjusted to meet different metering requirements.

[0052] A feed inlet 10 is opened at one end of the regulating cylinder 4 near the piston cylinder 3. The feed inlet 10 has a porous mesh structure inside, which uses tension to initially block the epoxy resin adhesive entering the metering chamber 11. Subsequently, under the push of the piston cylinder 3, it can ensure that the epoxy resin adhesive is fully discharged. A feed pump 12 is installed on the inner wall of the bottom of the regulating cylinder 4. The outlet of the feed pump 12 is connected to the discharge pipe 13. When the epoxy resin adhesive in the metering chamber 11 is pressed into the regulating cylinder 4, the feed pump 12 starts and transports the adhesive to the next stage of equipment through the discharge pipe 13.

[0053] The entire working process, through the coordinated operation of various components, enables the quantitative and interval delivery of epoxy resin adhesives, which facilitates the fulfillment of epoxy resin adhesive packaging requirements.

[0054] The accompanying drawings in this application are for illustrative purposes only. The dimensions and shapes of the components shown are not actual limitations but are merely schematic representations. In actual implementation, the components can be reasonably configured and adjusted according to specific needs and actual conditions.

[0055] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A conveying device for packaging epoxy resin adhesives, characterized in that, include: The storage tank (1) and the connecting cylinder (2) are provided with a feeding port (5) at the top of the storage tank (1) and a discharge end at the bottom of the storage tank (1) connected to the connecting cylinder (2). A piston cylinder (3) is slidably connected to one end of the connecting cylinder (2) and an adjusting cylinder (4) is slidably connected to the other end of the connecting cylinder (2). The piston cylinder (3) and the adjusting cylinder (4) form a metering chamber (11) inside the connecting cylinder (2). A drive assembly is connected to the piston cylinder (3) and is used to drive the piston cylinder (3) to reciprocate within the connecting cylinder (2); An adjustment component is connected to the adjustment cylinder (4) and is used to adjust the position of the adjustment cylinder (4) within the connecting cylinder (2); When the regulating cylinder (4) moves, the volume of the metering chamber (11) changes. When the piston cylinder (3) reciprocates, the epoxy resin adhesive in the metering chamber (11) can be squeezed out.

2. The conveying device according to claim 1, characterized in that, The drive assembly includes a first fixed plate (6) and a cylinder (8). The first fixed plate (6) is fixed to one end of the piston cylinder (3). The cylinder (8) is fixed to one side of the connecting cylinder (2) by a bracket. The piston rod of the cylinder (8) is connected to the first fixed plate (6) to drive the piston cylinder (3) to push and pull.

3. The conveying device according to claim 2, characterized in that, The adjustment assembly includes a second fixed plate (16), a motor (19), a drive gear (20), a screw (17), and a driven gear (21). The second fixed plate (16) is fixed to one end of the adjustment cylinder (4). The motor (19) is fixed on the second fixed plate (16). The output shaft of the motor (19) is connected to the drive gear (20). The screw (17) is rotatably connected to the second fixed plate (16). The driven gear (21) is fixed to one end of the screw (17) and meshes with the drive gear (20). A limiting plate (18) is provided on one side of the connecting cylinder (2). The screw (17) is threadedly engaged with the limiting plate (18). When the motor (19) is driven, the screw (17) rotates and drives the second fixed plate (16) and the adjustment cylinder (4) to move.

4. The conveying device according to claim 3, characterized in that, It also includes a guide rod (14) and a first proximity switch (15). The guide rod (14) is fixed to one side of the first fixed plate (6). The guide rod (14) slides through the limiting plate (18). The first proximity switch (15) is located at one end of the guide rod (14) and cooperates with one end of the screw (17). It also includes a fixed rod (7) and a second proximity switch (22). The fixed rod (7) is fixed to one end of the connecting cylinder (2) near the piston cylinder (3). The fixed rod (7) slides through the first fixed plate (6). The second proximity switch (22) is located at one end of the fixed rod (7) and cooperates with the first fixed plate (6). The first proximity switch (15) and the second proximity switch (22) are electrically connected to the cylinder (8) and are used to control the reciprocating motion of the cylinder (8).

5. The conveying device according to claim 4, characterized in that, One end of the fixed rod (7) is provided with a time relay (23), which is electrically connected to the second proximity switch (22) and is used to delay the trigger signal of the second proximity switch (22).

6. The conveying device according to claim 1, characterized in that, The regulating cylinder (4) has a feed inlet (10) at one end near the piston cylinder (3). The feed inlet (10) has a porous mesh structure to initially block the epoxy resin adhesive entering the metering chamber (11). The bottom discharge end of the storage tank (1) is equipped with a one-way valve (9) to prevent the epoxy resin adhesive from flowing back.

7. The conveying device according to claim 1, characterized in that, The bottom inner wall of the regulating cylinder (4) is provided with a feeding pump (12), and the outlet of the feeding pump (12) is connected to a discharge pipe (13). The discharge pipe (13) passes through one end of the regulating cylinder (4) and is used to transport the metered epoxy resin adhesive to the next equipment.

8. The conveying equipment according to claim 3, characterized in that, The limiting plate (18) is provided in multiple ways, and the screw (17) passes through multiple limiting plates (18) and is threadedly engaged with the limiting plate (18) near the second fixing plate (16).

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